An optimization processing means for optimizing constants of analogue circuits so as to satisfy given characteristic specification and design conditions has already existed. Specifically, a method is known that one objective function is constructed by summing plural weighted objective functions, and a combination of circuit constants which cause a value of the objective function to be minimized is searched by the simplex method. In this search processing, the optimization of the circuit constants is carried out so as to satisfy the requirement specification while changing the circuit configuration. However, when it is recognized that the requirement specification cannot be satisfied, it is necessary to repeat the same processing after returning to the first step and changing the requirement specification.
Because the circuit simulation should be repeated in the aforementioned search processing, it takes long time. If it is recognized that the requirement specification cannot be satisfied and the requirement specification is changed after returning to the first step, it takes further long time because the circuit simulation is further repeated. Thus, the conventional technique cannot substantially carry out the change of the requirement specification a lot of times.
Namely, the conventional technique cannot automatically design circuits close to the requirement specification in a short time regardless of a case where the requirement specification is satisfied or a case where the requirement specification is not satisfied.